Output power limit value calculation method and semiconductor process equipment

Abstract

The invention provides an output power limit value calculation method and semiconductor process equipment, the method is applied to a heating disc, the heating disc comprises a first heating piece and a temperature sensor, the temperature sensor is used for detecting the temperature of the first heating piece, and the method comprises the following steps: obtaining historical operation data of the first heating piece; wherein the historical operation data comprises historical output power and a temperature value detected by a temperature sensor; based on the output power and the temperature rise speed of the first heating piece in the historical operation data, the heat consumption power needed when the temperature of the first heating piece rises is determined, and the heat consumption power serves as the power lower limit value of the first heating piece in the temperature rise stage; and the heat supply power of the first heating piece at the preset temperature rising speed is calculated based on the heat consumption power, and the heat supply power serves as the power upper limit value of the first heating piece in the temperature rising stage. The temperature of the first heating piece can be prevented from generating large fluctuation, and the stability of temperature control is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of heating equipment, and in particular to an output power limit calculation method and semiconductor process equipment. Background Art

[0002] In semiconductor processing, the heating system of some semiconductor processing equipment (such as the heating plate heater for silicon wafers) usually includes two sets of heating elements that have a large impact on each other. One of the heating elements is equipped with a temperature control point (i.e., a temperature sensor), and the other heating element has no temperature control point. The heating element equipped with a temperature control point usually performs closed-loop control of the heating power based on the actual detected temperature, while the heating element without a temperature control point performs open-loop control of the heating power.

[0003] For heating elements with temperature control points installed, the relevant output power control technology usually adopts control algorithms such as proportional integral derivative (PID) control algorithm, inputs the temperature collected by the temperature control point into the temperature controller loop, controls the load according to the output value of the temperature controller, and sets the heating speed and limits the output power of the heating element. Limiting the output power of the heater is usually suitable for heating equipment with relatively large temperature hysteresis. The temperature hysteresis is generally caused by the long distance between the temperature control point and the heating element, or the small heat transfer coefficient of the heating equipment itself. The temperature detected by the temperature sensor reacts slowly, resulting in the heat output of the heating element being difficult to control. For example, the temperature sensor detects that the current temperature is less than the set value, the heating element continues to output power but the temperature still does not rise. The output power of the heating element continues to increase. When the temperature detected by the temperature sensor reaches the set value, because the heat output of the heating element accumulates more, the temperature continues to rise, and the temperature detected by the temperature sensor continues to exceed the set value. The output power of the heating element will decrease rapidly. However, since the temperature detected by the temperature sensor drops slowly, the output power of the heating element continues to decrease during this period, and the output power of the heating element is repeatedly controlled in this way. The larger the fluctuation range of the output power of the heating element, the greater the temperature fluctuation range. However, the relevant output power control technology does not set a reasonable output power range, and the calculated output power is often much larger than the actual required heat consumption power, resulting in large temperature fluctuations in the heating element and low temperature control stability. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide an output power limit calculation method and semiconductor process equipment, which can meet the heating power demand of the first heating element, and at the same time limit the fluctuation range of the output power of the first heating element, so that the heating capacity can be relatively stably converted into the heating rate, avoiding large fluctuations in the temperature of the first heating element, and improving the stability of temperature control.

[0005] In order to achieve the above purpose, the technical solution adopted by the embodiment of the present invention is as follows:

[0006] In a first aspect, an embodiment of the present invention provides an output power limit calculation method, which is applied to a heating plate of a semiconductor process equipment, wherein the heating plate includes a first heating element and a temperature sensor, wherein the temperature sensor is used to detect the temperature of the first heating element, and the output power limit calculation method includes: obtaining historical operation data of the first heating element; wherein the historical operation data includes historical output power and temperature values ​​detected by the temperature sensor; determining the heat consumption power required for heating the first heating element based on the output power and heating rate of the first heating element in the historical operation data, and using the heat consumption power as the lower power limit of the first heating element in the heating stage; calculating the heating power of the first heating element at a preset heating rate based on the heat consumption power, and using the heating power as the upper power limit of the first heating element in the heating stage.

[0007] Further, an embodiment of the present invention provides a first possible implementation of the first aspect, wherein the determining the heat consumption power required for the first heating element to heat up based on the output power and the heating rate of the first heating element in the historical operation data comprises: obtaining operation data of a preset time length from the historical operation data, recorded as target operation data; wherein the historical operation data also includes a curve of the temperature change of the first heating element over time, and the temperature of the first heating element produces multiple fluctuation cycles within the preset time length; based on each output power of the first heating element in the target operation data, calculating the average output power of the first heating element within the preset time length, and obtaining the heating rate setting value of the first heating element within the preset time length; obtaining operation data of a preset number of heating sections from the target operation data, and calculating the average output power and the average heating rate of the heating section based on the operation data of each heating section; wherein the heating section is a rising stage of the temperature detected by the temperature sensor; determining the heat consumption power required for the first heating element to heat up based on the average output power of the first heating element within the preset time length, the heating rate setting value, and the average output power and the average heating rate of the heating section.

[0008] Furthermore, the embodiment of the present invention provides a second possible implementation of the first aspect, wherein the calculation formula of the heat consumption power is:

[0009] P J =(T g *P p -P g *V p ) / (T g -V p )

[0010] Among them, P J is the heat consumption power, P p is the average output power of the first heating element within the preset time period, V p is the temperature rise speed setting value of the first heating element within the preset time, P g is the average output power in the heating stage, T g is the average heating rate in the heating section.

[0011] Further, the embodiment of the present invention provides a third possible implementation of the first aspect, wherein the calculation formula of the heating power is: S =T S *K P +P J ;

[0012] Among them, P S is the heating power, T S is the preset heating rate, K P is the proportionality coefficient between the power of the first heating element and the heating speed.

[0013] Further, the embodiment of the present invention provides a fourth possible implementation of the first aspect, wherein the calculation formula of the proportionality coefficient is: K P =(P g -P J ) / T g , or, K P =(P p -P J ) / V p .

[0014] Further, the embodiment of the present invention provides a fifth possible implementation of the first aspect, wherein the operating data of the heating section includes temperature data and output power data, and the calculating the average output power and the average heating speed of the heating section based on the operating data of each heating section includes: calculating the output power average value and the heating speed average value of each heating section based on the operating data of the heating section; calculating the average output power of the heating section based on the output power average value of each heating section; wherein the calculation formula of the average output power is: P g =(P g1 +P g2 +…+P gm ) / m,P gm is the average output power of the mth heating stage, P g is the average output power, m is the preset number; the average heating speed of the heating section is calculated based on the average heating speed of each heating section; wherein the calculation formula of the average heating speed is: Tg =(T g1 +T g2 +…+T gm ) / m,T g is the average heating rate, T gm is the average temperature rise rate of the mth temperature rise section.

[0015] In the second aspect, an embodiment of the present invention further provides a semiconductor process equipment, comprising: a heating plate, wherein the heating plate is used to heat the wafer to be processed; the heating plate comprises: a first heating element, a temperature sensor and a temperature controller; the temperature sensor is used to detect the temperature of the first heating element; the temperature controller is used to calculate the lower power limit value and the upper power limit value of the first heating element based on the output power limit calculation method described in any one of the first aspects, so as to limit the output power range of the first heating element.

[0016] Further, an embodiment of the present invention provides a first possible implementation manner of the second aspect, wherein the heating plate also includes a second heating element, and the distance between the temperature sensor and the first heating element is smaller than the distance between the temperature sensor and the second heating element; the temperature control mode of the first heating element is closed-loop control, and the temperature controller is used to determine the target output power of the first heating element based on the current temperature detected by the temperature sensor; the temperature control mode of the second heating element is open-loop following control, and the temperature controller is also used to control the output power of the second heating element based on the target output power, wherein the output power of the second heating element is positively correlated with the target output power.

[0017] Further, an embodiment of the present invention provides a second possible implementation of the second aspect, wherein the temperature controller is used to control the output power of the first heating element to be the upper power limit when the target output power is greater than the upper power limit; the temperature controller is also used to control the output power of the first heating element to be the lower power limit when the target output power is less than the lower power limit.

[0018] Furthermore, an embodiment of the present invention provides a third possible implementation scheme of the second aspect, wherein the first heating element and the second heating element are both annular heating tubes, the radius of the first heating element is smaller than the radius of the second heating element, and the second heating element is arranged on the outside of the first heating element, and the temperature sensor of the first heating element is located in the central area of ​​the annular heating tube.

[0019] The embodiment of the present invention provides an output power limit calculation method and semiconductor process equipment. By estimating the heat consumption power required for heating up a first heating element in a heating disk of the semiconductor process equipment and the heating power of the first heating element at a preset heating speed, and using the heat consumption power as the lower power limit of the first heating element in the heating stage, and using the heating power as the upper power limit of the first heating element in the heating stage, the heating power demand of the first heating element can be met, and at the same time, the fluctuation range of the output power of the first heating element is limited, so that the heating capacity can be relatively stably converted into the heating speed, thereby avoiding large fluctuations in the temperature of the first heating element and improving the stability of temperature control.

[0020] Other features and advantages of the embodiments of the present invention will be described in the following description, or some features and advantages can be inferred or determined without doubt from the description, or can be learned by implementing the above-mentioned techniques of the embodiments of the present invention.

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1a A schematic diagram of the structure of a heating system with a single temperature measuring point is shown;

[0024] Figure 1b A schematic diagram of the structure of a heating system with multiple temperature measurement points is shown;

[0025] Figure 1c A schematic diagram of the relevant temperature control principle is shown;

[0026] Figure 2 A flow chart of a method for calculating an output power limit value provided by an embodiment of the present invention is shown;

[0027] Figure 3 An example diagram of a temperature rise curve provided by an embodiment of the present invention is shown;

[0028] Figure 4 A schematic diagram of selecting a temperature rise section provided in an embodiment of the present invention is shown;

[0029] Figure 5a A temperature measurement graph showing a related temperature control technique;

[0030] Figure 5b A temperature measurement curve chart after setting the upper power limit and the lower power limit of the first heating element provided in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be described below in conjunction with the drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0032] At present, in semiconductor technology, some products sometimes have a heating system consisting of two heating elements that have a great influence on each other. According to the number of temperature control points, there are currently two situations for this heating system. The first situation is that the temperature control point can only be installed in one of the heating elements of the heating system, and the other heating element has no temperature control point and can only be open-loop controlled. The second situation is that the temperature control point can be installed in each of the two heating elements of the heating system, and both are closed-loop controlled.

[0033] In the first case, a temperature control point (i.e., a temperature sensor) is installed on one of the heating elements in the heating system, such as a round heating plate in the semiconductor field, which is used to heat silicon wafers, see Figure 1a The schematic diagram of the heating system structure with a single temperature measuring point is shown. The gray coil in the outer circle is the outer zone heating element, and the gray coil in the inner circle is the inner zone heating element. The two quadrilaterals are two temperature measuring points, one of which is used as a temperature control point. Due to the structure of the heating system, the outer zone cannot be equipped with a temperature measuring point. The temperature control point is relatively close to the inner zone heating element, so the temperature of the inner zone heating element can be detected.

[0034] In the second case, the temperature control points are installed in the heating elements of the heating system, such as the heating system of the chamber wall in the semiconductor field, see Figure 1b The schematic diagram of the heating system structure with multiple temperature measuring points is shown in FIG. Figure 1b The quadrilateral in the figure is a metal wall, the four large circles at the four corners inside the quadrilateral are heating elements, and the four small circles are temperature measuring points, that is, each heating element is provided with a corresponding temperature measuring point.

[0035] In the above two situations, when temperature control is performed, since the temperature measuring point is affected by the two heating systems, the temperature fluctuates during the heating process and after reaching the set value. Sometimes the effect is not ideal, which will cause bad process effects.

[0036] The first case currently uses a follow-up control method, that is, an open-loop controlled heating system. Because one of the heating elements does not have a temperature measurement point, its output power is calculated according to the output power of the closed-loop system. Because it is impossible to install a temperature measurement point, during the initial heating test, it can only be measured by special instruments under certain conditions and methods. After normal use, the actual temperature cannot be known. Some heating systems, such as Heater, have very high requirements for the temperature difference between the two heating elements. When the temperature difference exceeds a certain value, the heating element will be damaged.

[0037] For heating systems with temperature measurement points, most of the related temperature control technologies still use the traditional PID (Proportional Integral Derivative) control algorithm, see Figure 1c As shown in the schematic diagram of the temperature control principle, the actual temperature value collected at the temperature measuring point and the temperature set value are input into the input circuit of the temperature controller. The temperature controller calculates the power percentage and controls the load through the power regulator or solid-state relay. In addition, it also has the functions of setting the temperature rise rate and limiting the power output to ensure that the temperature rise rate is moderate. However, the limited power is usually estimated through experience or test data, and lacks verification and optimization. The following calculations on the output power are all calculations of the power percentage, referred to as power calculations.

[0038] The power limiting method is suitable for systems with relatively large temperature hysteresis. In the first case, although one of the heating elements is equipped with a temperature measuring point, there is still a certain distance between the temperature measuring point and the heating element. The temperature measuring point is slightly far from the heating element, or the heat transfer coefficient of the first heating element itself is relatively small. These factors will lead to temperature control lag and slow temperature response, resulting in the heating heat being difficult to control. For example, the current temperature is lower than the set value, the heating element continues to output power but the temperature still does not rise. The output power continues to increase. After reaching the set value, the heating element continues to rise because of the large amount of heat accumulation. Because it continues to exceed the set value, the output power will decrease rapidly, but the temperature will drop slowly. During this period, the output power continues to decrease, which will cause the temperature to deviate from the set value in the next cycle. Therefore, in this heating system, the larger the output power fluctuation range, the more likely it is to cause a larger temperature fluctuation range.

[0039] The second situation is to use two independent control systems, such as PID control algorithms, but because of the individual and environmental differences between the two heating elements, after reaching the temperature, the following situation may occur: one heating element has stopped heating, but the temperature is still rising, while the temperature of the other heating element has not reached the set value. Although the power output continues to increase, the temperature rise rate is very slow. For this situation, only through experimental data can the power of one of the heating elements with a higher temperature be limited. The specific value of the power limit needs to be repeatedly adjusted and verified. Therefore, in this case, the control effect of the two heating elements independently controlled may be lower than the control effect of the first situation. The control method of the first situation is usually used for temperature adjustment in the related technology.

[0040] In the relevant heating element temperature control technology, although control algorithms such as PID algorithm are used, which can sometimes achieve relatively good results, the temperature control of two heating elements that have a relatively large impact on each other is sometimes not ideal. The main problem is the lack of estimation of the heating power of the heating element. The output power of the heating element is often much larger than the actual required heat consumption power. Especially if there is an unexpected interruption or interference during the heating process, the temperature control will be more difficult and the temperature fluctuation will be relatively large when the heating is restarted.

[0041] In order to improve the above problems, an embodiment of the present invention provides an output power limit calculation method and a semiconductor process equipment, and the embodiment of the present invention is introduced in detail below.

[0042] This embodiment provides a method for calculating an output power limit. The method can be applied to a heating plate of a semiconductor process equipment. The heating plate includes a first heating element and a temperature sensor. The temperature sensor is used to detect the temperature of the first heating element. Figure 2 The output power limit calculation method shown in the flowchart mainly includes the following steps:

[0043] Step S202, obtaining historical operation data of the first heating element.

[0044] The above-mentioned historical operation data includes historical output power and temperature values ​​detected by the temperature sensor; during the operation of the first heating element, the temperature value of the first heating element is detected in real time or periodically based on the temperature sensor, and the data of temperature and output power changes over time are recorded.

[0045] In a specific embodiment, the heating plate further includes a second heating element, and the distance between the temperature sensor and the first heating element is smaller than the distance between the temperature sensor and the second heating element. Since the temperature sensor is closer to the first heating element, the temperature sensor is used to detect the current temperature of the first heating element.

[0046] Step S204, determining the heat consumption power required for heating the first heating element based on the output power and heating speed of the first heating element in the historical operation data, and using the heat consumption power as the lower limit of the power of the first heating element in the heating stage.

[0047] Since there is currently no formula for calculating the effect of the heat dissipation and heat consumption of the equipment on the temperature, the heating curve and the historical output power curve of the first heating element can be determined by obtaining the historical operation data of the first heating element, so that the relationship between the output power and the heating rate of the first heating element can be determined based on the historical operation data. Taking into account factors such as heat dissipation during the use of the first heating element, in order to heat up the first heating element (that is, the temperature detected by the temperature sensor gradually rises), the output power of the first heating element must reach a certain output power temperature before it starts to rise. According to the relationship between the heating rate and the output power of the first heating element during the heating process, the output power required for the first heating element to heat up can be determined, which is recorded as the heat consumption power. The heat consumption power is used as the lower limit of the power of the first heating element in the heating stage, that is, when the output power of the first heating element is greater than the lower limit, the first heating element starts to heat up; when the output power of the first heating element is less than or equal to the lower limit, the first heating element maintains the current temperature or cools down.

[0048] In order to determine the relationship between output power and heating rate, the thermodynamic formula Q N =C*M*ΔT,Q N is the heat, C is the specific heat, M is the mass, and ΔT is the temperature difference.

[0049] The inventors have found that by dividing both sides of the thermodynamic formula by time, with specific heat and mass as fixed constants, the thermal power P can be obtained. N and temperature rise rate V N The functional relationship between the output power and the heating rate can be determined according to the historical operation data of the first heating element.

[0050] Step S206, calculating the heating power of the first heating element at a preset heating speed based on the heat consumption power, and using the heating power as the upper limit of the power of the first heating element in the heating stage.

[0051] According to the relationship between the output power of the first heating element and the heating rate, the output power required for the first heating element to meet the preset heating rate can be calculated, which is recorded as the heating power. When the output power of the first heating element exceeds the heating power, it will result in a faster heating rate, exceeding the required heating rate and easily causing temperature fluctuations. Therefore, the heating power is used as the upper limit of the power of the first heating element in the heating stage.

[0052] In the actual heating process, the temperature rise curve detected by the temperature sensor is the most important monitoring data. Although the distance between the temperature sensor and the first heating element is smaller than the distance between the temperature sensor and the second heating element, the temperature sensor is used to detect the temperature of the first heating element. However, there is still a certain distance between the temperature sensor and the first heating element, which causes the temperature feedback of the first heating element to have a lag. The power output control using PID control sometimes still cannot solve the problem of large temperature fluctuations, overshoot and out of control. The main reason is that the heating power of the first heating element (i.e., the actual output power) is too large, and a lot of heat is accumulated in the first heating element. As time goes by, the heat is released. Although the power is reduced, the temperature rebounds.

[0053] The output power of the first heating element is not synchronized with the temperature change. This lag is related to the heat transfer coefficient of the material of the first heating element. For example, aluminum conducts heat much better than stainless steel and ceramics, has a small lag, and is relatively easy to control temperature. For a heating system with a single temperature control point and two heating elements, especially when the temperature control point is at different distances from the two heating elements, it is more difficult to control the temperature. Since the temperature fluctuation is mainly caused by the deviation of the heat supply from the actual required heat consumption, in order to reduce the temperature fluctuation, it is necessary to estimate the heat consumption power of the first heating element. By calculating the heating power based on the heat consumption power of the first heating element, the output power of the first heating element has a smaller limit range, resulting in smaller temperature fluctuations.

[0054] The above-mentioned output power limit calculation method provided in the present embodiment estimates the heat consumption power required for heating the first heating element and the heating power of the first heating element at a preset heating speed, and uses the heat consumption power as the lower power limit of the first heating element in the heating stage, and uses the heating power as the upper power limit of the first heating element in the heating stage. This can meet the heating power demand of the first heating element, and at the same time limit the fluctuation range of the output power of the first heating element, so that the heating capacity can be relatively stably converted into the heating speed, avoiding large fluctuations in the temperature of the first heating element, and improving the stability of temperature control.

[0055] In one embodiment, in order to improve the accuracy of heat consumption power calculation, this embodiment provides an implementation method for determining the heat consumption power required for heating the first heating element based on the output power and heating speed of the first heating element in the historical operation data, which can be specifically performed with reference to the following steps:

[0056] Step (1): Obtain operation data of a preset duration from historical operation data and record it as target operation data.

[0057] The above historical operation data also includes a curve of the temperature of the first heating element changing with time, and the temperature of the first heating element produces multiple fluctuation cycles within a preset time period.

[0058] Since there is no ready-made heat transfer formula in physics to calculate the relationship between the heat dissipation and heating power of the equipment and the temperature, it is necessary to collect the temperature rise curve and output power data of the first heating element through experimental methods, select a time period of operation data from the historical operation data of the first heating element for calculation according to the temperature rise and fall law, and then estimate the heating power and heat consumption power of the first heating element.

[0059] The above historical operation data also includes the temperature setting value. According to the characteristics of the temperature rise curve, the actual temperature detected by the temperature sensor will fluctuate above and below the temperature setting value. Taking into account the possible particularity of the local temperature range, a longer time period should be selected as much as possible. However, the longer the time period, the greater the temperature change. The heat consumption power of the first heating element will also change greatly when the temperature changes. Therefore, a compromise can be made. According to the temperature fluctuation law, 6-7 fluctuation cycles are selected as a calculation time period. The duration required for the 6-7 fluctuation cycles is the preset duration.

[0060] Step (2): Based on the output powers of the first heating element in the target operation data, the average output power of the first heating element within a preset time period is calculated, and a setting value of the heating speed of the first heating element within the preset time period is obtained.

[0061] The above historical operation data also includes a temperature rise speed setting value of the first heating element, obtains each output power point value of the first heating element within a preset time length recorded in the historical operation data, calculates the average output power of the first heating element within the preset time length, and obtains the temperature rise speed setting value V of the first heating element within the preset time length. p .

[0062] Average output power of the first heating element within a preset time period P p is the average output power of the heater within the preset time, n is the number of output powers recorded within the preset time, P i is the i-th output power value within the preset time length.

[0063] For example, see Figure 3 The temperature rise curve example shown in the figure, Figure 3 The example of the temperature rise curve and the corresponding power output curve of the first heating element within a preset time is provided in the text. During this period of time, the output power of the first heating element changes repeatedly, and the actual temperature value (i.e., the temperature detected by the temperature sensor) fluctuates around the temperature setting value. It can be approximately considered that the heat supply and heat consumption of the first heating element are basically balanced during this period of time, and the heat difference between the two realizes the temperature rise of the first heating element. The average output power P of the first heating element during this period of time is calculated. p , the power in this embodiment is calculated as a percentage of power.

[0064] Step (3): obtaining the operating data of a preset number of heating sections from the target operating data, and calculating the average output power and average heating speed of the heating sections based on the operating data of each heating section.

[0065] The temperature rise section is the rising stage of the temperature detected by the temperature sensor, that is, the line segment where the temperature rises from a trough to a peak.

[0066] The inventors have found that the actual temperature value detected in a certain period of time sometimes has a positive deviation from the temperature setting value, and sometimes has a negative deviation, which is generally the same as the fluctuation trend of the power output in the previous period of time. That is to say, if the temperature in this period has a positive deviation, the power output in the previous period of time is generally also a positive deviation, and vice versa. Therefore, in essence, the fluctuation of the output power will reflect the fluctuation of the same curve in the temperature after a period of time. The heat consumption power is assumed to be approximately unchanged over a period of time, and the temperature value of each point is generated based on the accumulation of the previous heating power. Based on this principle, see e.g. Figure 4 In the schematic diagram of temperature rise section selection shown in FIG. 1 , it can be considered that the temperature section encircled by the first circle is mainly affected by the power section encircled by the first rectangular frame, and the temperature section encircled by the second circle is mainly affected by the power section encircled by the second rectangular frame. A preset number of temperature rise section operation data can be selected from the operation data of the preset duration. The preset number can range from 2 to 5, and the preferred value is 3. Figure 4 As shown, three temperature rise sections can be selected and the average output power and average temperature rise rate of the three temperature rise sections can be calculated.

[0067] In a specific implementation, the average output power and the average heating speed of each heating section are calculated based on the operation data of the heating section;

[0068] The average output power of the heating section is calculated based on the average output power of each heating section; the calculation formula of the average output power is:

[0069] P g =(P g1 +P g2 +…+P gm ) / m,

[0070] P g1 is the average output power of the first heating stage, P g2 is the average output power of the second heating stage, and so on, P gm is the average output power of the mth temperature rise section (i.e., the average of the maximum output power and the minimum output power of the temperature rise section, or the average of each output power), P g is the average output power, and m is the preset number, i.e. the number of heating stages.

[0071] Since the change in the actual output power of the first heating element is based on the output of the PID control algorithm, it is not linear. The greater the deviation from the temperature setting value, the faster the output power changes and the faster it reaches the peak. The temperature change is also not linear because it is also affected by the current real-time heating power. Even when the output power decreases, as long as the output power is greater than the heat consumption of the equipment, it will still increase the temperature. In order to simplify the calculation, the average output power of each heating section can be calculated according to the average value of the peaks and troughs in the figure.

[0072] The average heating rate of the heating section is calculated based on the average heating rate of each heating section; wherein the calculation formula of the average heating rate is:

[0073] T g =(T g1 +T g2 +…+T gm ) / m,

[0074] T g is the average heating rate, T g1 is the average heating rate of the first heating stage, T g2 is the average heating rate of the second heating stage, T gm It is the average temperature rise rate of the mth temperature rise section (the difference between the maximum temperature and the minimum temperature of this temperature rise section divided by the time difference).

[0075] Step (4): Determine the heat consumption power required for heating the first heating element based on the average output power of the first heating element within a preset time period, the set value of the heating speed, and the average output power and average heating speed of the heating section.

[0076] The above thermodynamic formula Q N =C*M*ΔT, dividing both sides of the formula by time can give the power P N and heating rate V N Proportional, we can get:

[0077] (P g -P J ) / T g =(P p -P J ) / V p =K P

[0078] The average output power P of the first heating element within a preset time period p , Heating speed setting value V p And the average output power P in the heating stage g and the average heating rate T g, input the above formula, and you can calculate the heat consumption power P J And the proportionality coefficient K between the power of the first heating element and the heating rate P .

[0079] In a specific implementation, the calculation formula for heat consumption power is:

[0080] P J =(T g *P p -P g *V p ) / (T g -V p )

[0081] Among them, P J is the heat consumption power, P p is the average output power of the first heating element within a preset time, V p is the temperature rise rate setting value of the first heating element within the preset time, P g is the average output power in the heating stage, T g is the average heating rate in the heating stage.

[0082] For example, referring to the operation data table of the first heating element shown in Table 1 below, the heat consumption power of the first heating element is calculated according to the data in Table 1:

[0083] Table 1 Operation data table of the first heating element

[0084]

[0085]

[0086] Then P p =(28%+65%+5%+83%+78%+5%+23%+42%+32%) / 11=32.8%

[0087]

[0088] The heating power can also be calculated based on the proportional relationship between power and heating rate.

[0089] (P S -P J ) / T S =(P p -P J ) / V p =K P

[0090] In one embodiment, the calculation formula for heating power is: P S =T S *KP +P J

[0091] Among them, P S is the heating power (%), T S is the preset heating rate (°C / min). When the first heating element needs to meet a certain temperature rise rate, the required preset heating rate can be input into the above heating power calculation formula, the heating power can be calculated, and the output power of the first heating element is controlled to be the heating power, then the heating rate of the first heating element is the preset heating rate.

[0092] In one embodiment, the calculation formula of the proportionality coefficient is: K P =(P g -P J ) / T g , or, K P =(P p -P J ) / V p , K P is the proportional coefficient between the power of the first heating element and the heating speed.

[0093] For example, based on the operating data of the first heating element provided in Table 1 above, when the required heating rate of the first heating element is T S =5℃ / min,

[0094] Heating power

[0095] See the following table 2 for the heat consumption power of the first heating element and the heating power data table when the preset heating rate is 5°C / min:

[0096] Table 2 Data table of heat consumption power of the first heating element and heating power when the preset heating rate is 5℃ / min

[0097]

[0098] According to Table 2 above, when the temperature range of the first heating element is 200-300°C, if the first heating element is required to heat at a heating rate of 5°C / min, limiting the power of the first heating element to between 30.5% and 34.4% can reduce temperature fluctuations.

[0099] See Figure 5a The temperature measurement value curve graph and Figure 5b The temperature measurement value curve diagram after setting the upper power limit and the lower power limit of the first heating element is shown, Figure 5a The temperature curve detected after the power of the first heating element is controlled by using the existing temperature control technology is shown. Figure 5bThe temperature curve detected after limiting the upper power limit and the lower power limit of the first heating element by the method provided in this embodiment is shown. Figure 5a and Figure 5b It can be seen that after setting the upper power limit and the lower power limit of the first heating element, the fluctuation of the temperature measurement value is significantly reduced, and the temperature stability is improved.

[0100] The method for calculating the output power limit of the above-mentioned first heating element provided in this embodiment calculates the heat consumption power and heating power of the first heating element for the heating system with a single temperature measuring point and two first heating elements, and then estimates the range of the heating power of the first heating element, so that the heating heat can be relatively stably converted into the temperature rise rate, thereby achieving a good temperature following effect and improving the stability of temperature control.

[0101] Corresponding to the output power limit calculation method provided in the above embodiment, an embodiment of the present invention provides a semiconductor process equipment, including: a heating plate, the heating plate is used to heat a wafer to be processed;

[0102] The heating plate comprises: a first heating element, a temperature sensor and a temperature controller; the temperature sensor is used to detect the temperature of the first heating element;

[0103] The temperature controller is used to calculate the lower power limit value and the upper power limit value of the first heating element based on the output power limit calculation method provided in the above embodiment, so as to limit the output power range of the first heating element, that is, to limit the output power of the first heating element within the range of the lower power limit value to the upper power limit value, so as to narrow the temperature fluctuation range of the first heating element and improve the stability of the temperature control of the first heating element.

[0104] In one embodiment, the heating plate provided in this embodiment also includes a second heating element, and the distance between the temperature sensor and the first heating element is smaller than the distance between the temperature sensor and the second heating element; the temperature control method of the first heating element provided in this embodiment is closed-loop PID control, and the temperature controller is used to determine the target output power of the first heating element based on the current temperature detected by the temperature sensor; the current temperature and target temperature of the first heating element detected by the temperature sensor are input into the PID controller to obtain the target output power of the first heating element, thereby realizing closed-loop PID control of the temperature of the first heating element.

[0105] The temperature control method of the second heating element is open-loop following control, and the temperature controller is also used to control the output power of the second heating element based on the target output power, wherein the output power of the second heating element is positively correlated with the target output power, that is, the output power of the second heating element = target output power * preset proportional coefficient, and the proportional coefficient is related to the type of process to be performed on the wafer to be processed. For example, when the temperature value requirement of the wafer position corresponding to the second heating element during the process is higher, the proportional coefficient value is larger, and the output power of the second heating element changes with the target output power of the first heating element, thereby realizing open-loop following control of the second heating element.

[0106] In one embodiment, the temperature controller provided in this embodiment is used to control the output power of the first heating element to be the upper power limit value when the target output power is greater than the upper power limit value;

[0107] The temperature controller is also used to control the output power of the first heating element to be the power lower limit value when the target output power is less than the power lower limit value.

[0108] In one embodiment, the first heating element and the second heating element provided in this embodiment are both annular heating tubes, the radius of the first heating element is smaller than the radius of the second heating element, and the second heating element is arranged on the outside of the first heating element, and the temperature sensor of the first heating element is located in the central area of ​​the annular heating tube, that is, close to the center point.

[0109] Exemplarily, as shown in FIG1 , the second heating element can be a gray annular heating tube in the outermost ring, and the first heating element includes two adjacent gray annular heating tubes in the inner ring; the temperature sensor is one of the rhombuses at the center of the circle, and the temperature sensor is close to the first heating element and can be used to detect the current temperature of the first heating element.

[0110] The device provided in this embodiment has the same implementation principle and technical effects as those of the aforementioned embodiments. For the sake of brief description, for matters not mentioned in the device embodiment, reference may be made to the corresponding contents in the aforementioned method embodiment.

[0111] An embodiment of the present invention provides a computer-readable medium, wherein the computer-readable medium stores computer-executable instructions. When the computer-executable instructions are called and executed by a processor, the computer-executable instructions prompt the processor to implement the method described in the above embodiment.

[0112] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system described above can refer to the corresponding process in the aforementioned embodiment, and will not be repeated here.

[0113] The computer program product of the output power limit calculation method provided in the embodiment of the present invention includes a computer-readable storage medium storing program code, and the instructions included in the program code can be used to execute the method described in the previous method embodiment. The specific implementation can be referred to the method embodiment, which will not be repeated here.

[0114] In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0115] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0116] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0117] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for calculating an output power limit, characterized in that: A heating plate applied to semiconductor process equipment, the heating plate comprising a first heating element and a temperature sensor, the temperature sensor being used to detect the temperature of the first heating element, the output power limit calculation method comprising: Acquire historical operation data of the first heating element; wherein the historical operation data includes historical output power and temperature values ​​detected by the temperature sensor; Determine the heat consumption power required for heating the first heating element based on the output power and heating speed of the first heating element in the historical operation data, and use the heat consumption power as the lower limit of the power of the first heating element in the heating stage; The heating power of the first heating element at a preset heating speed is calculated based on the heat consumption power, and the heating power is used as the upper limit of the power of the first heating element in the heating stage.

2. The method for calculating the output power limit according to claim 1, characterized in that: The determining the heat consumption power required for heating the first heating element based on the output power and the heating speed of the first heating element in the historical operation data includes: Obtaining operation data of a preset time length from the historical operation data, and recording it as target operation data; wherein the historical operation data also includes a curve of the temperature of the first heating element changing with time, and the temperature of the first heating element has multiple fluctuation cycles within the preset time length; Based on each output power of the first heating element in the target operation data, calculating the average output power of the first heating element within the preset time length, and obtaining a temperature rise speed setting value of the first heating element within the preset time length; Acquire a preset number of operation data of the temperature rise sections from the target operation data, and calculate the average output power and average temperature rise speed of the temperature rise section based on the operation data of each temperature rise section; wherein the temperature rise section is a rising stage of the temperature detected by the temperature sensor; The heat consumption power required for heating the first heating element is determined based on the average output power of the first heating element within the preset time period, the temperature rise rate setting value, and the average output power and average temperature rise rate of the temperature rise section.

3. The method for calculating the output power limit according to claim 2, characterized in that: The calculation formula of the heat consumption power is: P J =(T g *P p -P g *V p ) / (T g -V p ) Among them, P J is the heat consumption power, P p is the average output power of the first heating element within the preset time period, V p is the temperature rise speed setting value of the first heating element within the preset time, P g is the average output power in the heating stage, T g is the average heating rate in the heating section.

4. The method for calculating the output power limit according to claim 3, characterized in that: The calculation formula of the heating power is: P S =T S *K P +P J ; Among them, P S is the heating power, T S is the preset heating rate, K P is the proportionality coefficient between the power of the first heating element and the heating speed.

5. The method for calculating the output power limit according to claim 4, characterized in that: The calculation formula of the proportionality coefficient is: K P =(P g -P J ) / T g , or, K P =(P p -P J ) / V p .

6. The method for calculating the output power limit according to claim 2, characterized in that: The operation data of the heating section includes temperature data and output power data, and the calculation of the average output power and the average heating speed of the heating section based on the operation data of each heating section includes: Calculating the average output power and the average heating speed of each heating section based on the operating data of the heating section; The average output power of the heating section is calculated based on the average output power of each heating section; wherein the calculation formula of the average output power is: g =(P g1 +P g2 +…+P gm ) / m,P gm is the average output power of the mth heating stage, P g is the average output power, and m is the preset number; The average heating rate of each heating section is calculated based on the average heating rate of each heating section; wherein the calculation formula of the average heating rate is: g =(T g1 +T g2 +…+T gm ) / m,T g is the average heating rate, T gm is the average temperature rise rate of the mth temperature rise section.

7. A semiconductor process equipment, characterized in that: include: A heating plate, the heating plate is used to heat the wafer to be processed; The heating plate comprises: a first heating element, a temperature sensor and a temperature controller; the temperature sensor is used to detect the temperature of the first heating element; The temperature controller is used to calculate the lower power limit and the upper power limit of the first heating element based on the output power limit calculation method according to any one of claims 1 to 6, so as to limit the output power range of the first heating element.

8. The semiconductor process equipment according to claim 7, characterized in that: The heating plate further comprises a second heating element, and the distance between the temperature sensor and the first heating element is smaller than the distance between the temperature sensor and the second heating element; The temperature control method of the first heating element is closed-loop PID control, and the temperature controller is used to determine the target output power of the first heating element based on the current temperature detected by the temperature sensor; The temperature control method of the second heating element is open-loop following control, and the temperature controller is also used to control the output power of the second heating element based on the target output power, wherein the output power of the second heating element is positively correlated with the target output power.

9. The semiconductor process equipment according to claim 8, characterized in that: The temperature controller is used for controlling the output power of the first heating element to be the upper power limit when the target output power is greater than the upper power limit; The temperature controller is further configured to control the output power of the first heating element to be the power lower limit value when the target output power is less than the power lower limit value.

10. The semiconductor process equipment according to any one of claims 8 to 9, characterized in that: The first heating element and the second heating element are both annular heating tubes, the radius of the first heating element is smaller than the radius of the second heating element, and the second heating element is sleeved outside the first heating element, and the temperature sensor of the first heating element is located in the central area of ​​the annular heating tube.

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